A pressurized-water reactor pressure vessel has coolant pipes radiating from its upper portion and connecting with steam generators. With temperature changes, the vessel thermally expands and contracts.
To prevent such thermally induced motion from unduly stressing the coolant pipes, the vessel may be supported adjacent to the pipes which radiate from its upper portion. For greater support it is desirable to also support the vessel via its bottom, but this introduced the problem that if the vessel is supported mainly via its bottom its vertical thermal expansion and contraction motions displace the coolant pipes and place undesirable stresses on them and their connections with the vessels and the steam generators.